The invention relates to a scroll compressor, wherein the bearings for mounting the drive shaft are formed of a material that will cause wear to the shaft when the shaft becomes misaligned.
Scroll compressors are becoming widely utilized in many compression applications. Essentially, a scroll compressor includes a first scroll which orbits relative to a second scroll. Both members have a base and a generally spiral wrap extending from the bases. The two wraps interfit to define compression chambers. When the orbiting scroll orbits, the size of the chambers decreases to compress an entrapped refrigerant.
Scroll compressors are very popular because they are efficient. However, they present many design challenges in that there are a number of forces on the compressor components. One problem that occurs in the scroll compressor relates to the mounting of the shaft. A shaft drives the orbiting scroll through an electric motor. The shaft is mounted in an upper bearing and a lower bearing. An eccentric pin from the shaft is received in a slider block mounted in an upper bearing in the first scroll.
In the past, the three bearings have sometimes been misaligned. One type of scroll compressor shaft is cantilevered in the upper bearing. When bearing misalignment occurs with this type compressor, the shaft moves to an angle which is non-parallel to the central axis of the bearings. When this happens, there is contact between the edges of the bearings, and the outer surface of the shaft and slider block. There is the edge loading between the shaft and slider block, and the bearings at the edges that are in contact. Seizure of the shaft can result, and there is also inadequate lubricant flow to the contact area.
Scroll compressors have sometimes utilized carbon containing bearings to mount the shaft. However, this type of bearing has only been utilized in a male mounted scroll compressor shaft, which does not have the cantilevered shaft. In this type of scroll compressor, there is no danger of edge loading.